A fully compositional streamline simulator for unsteady state two-phase flow in gas condensate systems

A fully compositional streamline simulator has been developed to simulate unsteady-state two-phase flow in gas condensate systems. This model uses the unsteady-state line source and sink solution (in the form of gas pseudo-pressure) to the real gas diffusivity equations and flow along pathlines to simulate flow and pressure in the reservoir. The conductivity ratio method is used to adjust reservoir pressures for the effect of two phases. The properties of vapor and liquid phases are obtained via vapor liquid equilibrium calculations that are done using equilibrium coefficients. These equilibrium coefficients are computed from empirical correlations as functions of pressure, temperature and convergence pressure.; In addition to the normal results obtained from similar simulators, this model calculates the physical properties of the mixture. These properties include critical temperature and pressure, the dewpoint pressure at the critical temperature, and the cricondentherm temperature and the dewpoint pressure at this temperature. Also, the upper and lower dewpoint pressures at reservoir temperature are given by the program if the mixture is a gas condensate system.; This model serves as a new general type of primary recovery predictor for the pressure depletion recovery process for gas condensate reservoirs. This program was built to run on a personal computer and can be applied to reservoirs of any shape or size and containing any number of wells.; Favorable results were obtained when compared to the analytical solution for a well in the center of circular reservoir that was homogeneous, isotropic, and of constant thickness. Comparison of this model with a commercial finite-difference simulator, ECLIPS-300, that uses a cubic equation of state (Peng-Robinson) showed that results from our model match results from ECLIPS-300 model if they both use the same PVT data.